Void Pointer Problem

[Peterwkc]

Hello programmer from all around the word, i have a noob question.

Some function in C header files are accept a pointer to any type but how the function what type is it and allocating the memory for the variable/object.

Thanks for your help.


Your help is greatly appreciated by me and others.

[Peterwkc]

Is this question for expert ? As i know, void pointer is a low level operation.

A billion thanks to any suggestions and recommendations.

[Banfa]

Generally speaking when a function takes a void * it is because it does not need to know the data type because it works on any datatype. For instance

void * memcpy ( void * destination, const void * source, size_t num );

It does not need to know the type of data its parameters are pointing to, it just copies data between 2 memory locations.

[Peterwkc]

Then, how the function know copies how mnay bytes?

Sorry for my stupidness.

Thanks.

[Banfa]

Then, how the function know copies how mnay bytes?

That is supplied as the third parameter to the function, follow the link I provided and read about it.

Again in general when providing pointers to unknown types you usually have to provide the size of the data as well.